Interlock switch and receptacle



July 14, 1953 w. E. PARISH INTERLOCK SWITCH AND RECEPTACLE Filed Feb. 20, 1951 INVENTOR. %zumifimmfl BY 3,7404% 7% tacle chamber and a switch chamber.

Patented July 14, 1953 UNITED STATES PATENT OFFICE INTERLOCK SWITCH AND RECEPTACLE Willard E. Parish, Syracuse,.N.. Y.,, assignor to Grouse-Hinds Company, Syracuse, N. Y., a corporation of New York Application Feb1'uary20, 1951, Serial No. 211,855

1 3 Claims. 1

This invention relates to a combination switch and receptacle unit, and more particularly to a unit of that type havin a receptacle adapted to receive an ordinary attachment plug as ordinarily found on the cords of appliances.

The invention has as an object a receptacle and switch unit embodying a structure cooperable to prevent withdrawal of the plug from the receptacle, or insertion of the plug in the receptacle while the switch is in the on position.

The invention has as a further object a unit of the type referred to embodying a receptacle mounting structure cooperable with the plu inline 2-2, Figure 1.

Figure 3 is a sectional view taken on line 33, Figure 2.

Figure 4 is a front elevational view of a portion of the front of the unit with the trim cover removed.

The unit consists of a rigid housing ll] preferably formed of cast metal and having a recep- Both of these chambers open through the back or rear side of the housing, and the receptacle chamber also opens through the front or forward side of the housing. The rear portion of the chambers are threaded to receive sleeves the outer ends of Which are threaded internally to receive circular termina1 blocks I2 formed of insulating material, such as a molded plastic, and having termina1 inserts into the end of which are threaded terminal screws I3.

The receptacle I4 is of circular formation on its exterior surface and is slidably mounted in the forward portion of the receptacle chamber. The receptacle I4 is formed with contacts l5, one of which is shown in Figure 1, for the reception of the prong contacts of a conventional plug indicated in dotted outline at l6, Figure 2. The receptacle is formed with an annular shoulder |1 into which there is threaded a screw IS, the head of which is slidably mounted in a slot or keyway l9 formed in the outer portion of the receptacle chamber. The screw |8 prevents rotation of the receptacle and also movement of the receptacle outwardly of the chamber by the screw contacting a plate 2| attached to the face of the housing by screws 22. v

A coiled compression spring is positioned in the sleeve l| intermediate the terminal block l2 and the receptacle I4, and serves to yieldingly urge the receptacle outwardly, this movement being arrested by the screw l8 engaging the cover member 2 I, see Figure 2.

A switch 26 is mounted in the switch chamber, the switch being fixedly secured to a disk 21 clamped between the inner end of the sleeve H and an internal annular shoulder 28. This shoulder is formed with a notch 29 to receive an ear 3!] bent up from the periphery of the disk and which functions to hold the disk and the switch against rotation in the housing.

The face wall of the housing is formed with a threaded aperture to receive a threaded shaft 32, and to the inner end of which there is fixedly secured a member 33 having an elongated opening in which there isslidably mounted a grom- 1 met 34 and which encircles the actuating handle 35 of the switch. This arrangement is such that upon oscillation of the shaft 32, the switch is moved to on and off positions. The switch is connected to the leads 36 by conductors 3'! and the receptacle is connected to the leads 38 by the conductors 39.

- A handle 40 is affixed to the outer end of the shaft 32 to provide for the convenient oscillation of the shaft. The shaft, the member 33, and the handle 40 form an actuator to actuate the switch 26 to on and off positions.

The plate 2| is formed with a pair of outwardly extending ears 4| between which a cover member 42 is arranged. The cover is hinged on a rod 43 secured at its ends to the ears 4| as by screws 44. The upper portion of the cover member 42 is of circular form to enclose the face of the receptacle M, the cover member being formed with a slot 45 extending downwardly from its upper edge to receive the cord 4'! to which the plug is attached. The cover 42 is yieldingly urged to closed position, illustrated in Figure 2, by a torsion spring 48. The lower portion of the cover 42 is formed with a circular aperture 49 communicating with a slot to. The aperture 49 and slot 5!} permit the cover to be swung outwardly from the face of the unit, as shown at dotted outline 5|, Figure 2. When in this position, the plug Hi can be inserted in the receptacle and withdrawn therefrom and at which time the handle 40 of the switch actuator is in vertical position, as shown in Figures 1 and 2, and the switch is in the off position. After the plug is inserted in the receptacle, the cover 42 is permitted to move to closed position, as shown in Figure 2, at which time the handle member 40 is positioned exteriorly of the cover and can be moved to the dotted outline position 54, Figure 1, moving the switch into the on position. As long as the handle is in this latter position with the switch on, the cover 42 can not be moved outwardly away from the unit about the pivot 43 because of the interference afforded by the position of the handle indicated at 54, Figure 1, as will be apparent.

Attachment plugs, as indicated at 56, Figure 2, are various forms and shapes, and in order that the unit may be used with such various shapes and sizes of plugs, the receptacle M is movable inwardly against the action of the spring 25 to accommodate plu s of longer length. A dishshaped trim cover may be applied to the face of the fitting as by screw and is formed with a radial flange 58 for abutment against the wall or panel, or other surface on which the unit may be mounted.

This combination switch and receptacle unit is of the explosion-proof type due to the fact that the switch is mounted in an explosion proof chamber provided for by the sleeve H threading into th rear side of the housing 58 and the terminal plug i2 threading into the outer end of the sleeve. These units are particularly useful in such places as hospital operatin rooms and other hazardous locations where doctors and others bring their own electrical appliances which are provided with lead cords having ordinary or conventional attachment plugs.

As will be apparent, the circuit is established and broken by the switch in the explosion-proof housing with the arrangement to prevent withdrawal or insertion of the plug unless the switch is in the off position.

What I claim is:

l. A combination receptacle and switch unit comprising a housing, a switch mounted in the housing and having an actuating member extending forwardly through the face of the housing, a receptacle mounted in the housing and having plug receiving contacts exposed in the face of the housing, a cover member pivotally mounted on the housing and being movable from open to closed positions and being operable in closed position to restrain separation of a plug from the receptacle, and said actuating member having a portion overlying said cover when the switch is in th on position to prevent movement of the cover from closed to open position.

2. A combination receptacle and switch unit comprising a housing, a switch mounted in the housing and having an actuating member operable eXteriorly of the face of the housing, said housing being formed with a recess in the face thereof, a receptacle slidably mounted in said recess toward and from the face of the housing and having plug engaging contacts exposed in the face of the housing, means yieldingly restraining inward movement of the receptacle, acover pivotally mounted on the face of the housing and being movable about its pivot in juxtaposition to said recess and being operable in said position to enclose a plug positioned in the receptacle and to prevent separation of the plug from the receptacle, said switch actuator being cooperable with said cover when the switch is in the on position to lock the same against outward movement.

3. A combination switch and receptacle unit comprising a housing formed with an aperture in the rear wall thereof, a cylindrical member detachably mounted in said wall, a switch mounted in said cylindrical member, a closure for the open end of said member detachably secured thereto, said housing being formed with a passage extending therethrough from the face side of the housto the rear side thereof, a cylindrical member detachably mounted in said passage at the rear side of the housing, a receptacle slidably mounted in said passage and having contacts exposed at the face side of the housing, a closure detachably mounted in said cylindrical member, a spring interposed between the receptacle and said closure and being operable to yieldingly urge the receptacle toward the face side of the housing, a cover pivotally mounted at one end to the face side of the housing and being movable about its pivot toward the housing in juxtaposition to the receptacle to enclose a plug positioned in the receptacle, a switch actuating member operable exteriorly of the face side of the housing and being cooperable when said switch is in th on position to prevent outward movement of said cover.

WILLARD E. PARISH.

References Cited in the file Of this patent UNITED STATES PATENTS Abraham Apr. 13, 1948 

